The present invention relates to an image forming apparatus having a cleaning device and a cleaning method.
Conventionally, in an image forming apparatus, to remove unnecessary toner adhered to a photosensitive surface of a photoconductor and a transfer surface of an intermediate transfer medium, a cleaning device is used. In the cleaning device, a cleaning blade is used. The cleaning blade has a front end arranged so as to make contact with and separate from the photosensitive surface and transfer surface and scrapes off unnecessary toner adhered to the photosensitive surface and transfer surface.
FIG. 4 shows the constitution of the circumference of a cleaning device of a conventional image forming apparatus. As shown in FIG. 4, a cleaning device 9 of the conventional image forming apparatus removes unnecessary toner adhered to the transfer surface of an intermediate transferring belt 3.
The cleaning device 9 is installed so as to rotate with a rotating shaft R′ as a rotational center. The front end of a cleaning blade 901 is pressed against a cleaned surface by a pressing unit 2 composed of a tension spring.
Further, when separating the cleaning blade 901 from the cleaned surface, the cleaning blade 901 is separated against pressing force (in the direction F shown in the drawing) of the pressing unit 2 using a cam (not shown).
By use of the constitution of the cleaning device 9 of the conventional image forming apparatus aforementioned, to make the cleaning blade 901 contact with the cleaned surface, when released from control force by the cam, the front end of the cleaning blade 901 moves toward the cleaned surface by the pressing force applied by the pressing unit 2.
In such a constitution, when the force by the pressing unit 2 is strong, the front end of the cleaning blade 901, as shown by a dashed line in the drawing, is applied with higher pressure than the contact pressure originally appropriate to cleaning, thereby the front end of the cleaning blade 901 is excessively cut into the cleaned surface (hereinafter, referred to as “excessive cutting”). That is, the cleaning blade 901 and cleaned surface are applied with an excessive load and there is a possibility that the cleaning blade 901 and cleaned surface may be adversely affected in the span of life.